Experimental and numerical study of pocket base connections for steel latticed columns under cyclic loadings

Pocket base connections for steel latticed columns are increasingly being applied in single-story industrial workshops. However, basic research on this type of column bases remains limited. In this study, bond strength tests for old-to-new concrete interfaces and push-out tests for steel–concrete interfaces were conducted to determine their characteristic strengths. Combined with previous full-scale quasi-static tests, finite element models (FEMs) were established considering the material, geometry, and boundary condition nonlinearities, and then verified against the test results. During modelling, the cohesive model was adopted to simulate nonlinear interfacial behaviors, calibrated using experimentally measured bond strengths. Predictions from the current design formula in the Chinese code were assessed by comparisons with simulation results. Test results demonstrated that the interfacial bond strength between C30 concrete and cementitious grout was 62.1 % higher in the normal direction and 51.7 % higher in the tangential direction, respectively, compared to that between C30 concrete and C40 fine aggregate concrete. Moreover, the ultimate bond strength of steel–C40 fine aggregate concrete interfaces was 2.44 times that of steel–cementitious grout interfaces . Developed FEMs effectively simulated the mechanical properties, failure modes, and crack distributions. However, the design formula tended to overestimate bearing capacities. This study demonstrated the potential applicability of pocket base connections for steel latticed columns, and developed FEMs provided a solution for conducting further parametric analyses with promising results. • Bond strength tests for old-to-new concrete interfaces and push-out tests for steel–concrete interfaces were conducted. • The bond strength test results were used for the cohesive model to simulate the interfacial behaviors. • Based on previous tests, finite element models of pocket base connections for steel latticed columns were established. • The accuracy of the design formula in the Chinese code was evaluated based on the simulation results.